Phylum Euglenophyta (Euglena)
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Small phylum of the Kingdom protista, consisting of mostly unicellular aquatic algae. Many of these organisms exhibit characteristics similar to both plants and animals. organisms of this phylum are also called Euglenozoa, euglenoids, euglenophytes among others. This is a comprehensive presentation. It will guide you in identifying Euglena.
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Phylum Euglenophyta (Euglena)
- 1. Phylum Euglenophyta Presented by: Fasama H. Kollie Lecturer, Department of Biology Mother Patern College of Health Sciences February 14, 2019
- 2. Lesson Outline 1. Overview of the phylum Euglenophyta 2. Characteristics of Euglena • Habit & habitat of Euglena viridis, structure, movement, nutrition • Respiration 4. Reproduction in Euglena 3. Ecological & economic importance
- 3. • Upon completion of this lesson, students will be able to; 1. Describe the general characteristics and structures of Euglena 2. Describe movements in Euglena 3. Describe the process of reproduction 4. Identify and explain some ecological and economic importance of euglena to human Lesson Objectives
- 4. Overview of The Phylum Euglenophyta • Euglenophyta is a small phylum of the kingdom protista, consisting of mostly unicellular aquatic algae • Of the protist kingdom, many of these organism exhibit characteristics of both plants and animals • Most live in freshwater; many have flagella and are motile • Organisms of this phylum are also called euglenozoa, euglenoids, euglenophytes
- 5. Overview Cont’d • Consist of 54 genera and approximately 800 species • Example; Euglena, Astasia, Trachelomonas, Colacium, Phacus, Peranema, Petalomonas, Cantusaygni… • The most characteristic genus is Euglena which consist of different species • Eg: Euglena spirogyra, E. viridis, E. gracilis etc
- 6. Euglena viridis DOMAIN: Eukarya KINGDOM: Protista PHYLUM: Euglenophyta CLASS: Euglenoidea ORDER: Euglenales FAMILY: Euglenaceae GENUS: Euglena SPECIES: viridis
- 7. Habit and Habitat of Euglena viridis • Euglena viridis is a solitary and free living freshwater organism • It is found in freshwater pools, ditches and slowly running streams • It is found in abundance where there is considerable amount of vegetation
- 9. Structure of Euglena viridis • SHAPE: • Euglena viridis is elongated and spindle-shaped in appearance.
- 10. Structure of Euglena viridis Cont’d • SIZE: • Euglena viridis is about 40-60 microns in length and 14-20 microns in breadth at the thickest part of the body. 40 – 60 µ 14 – 20 µ
- 11. • Pellicle: • The body is covered by a flexible, tough and strong cuticular periplast which lies beneath the plasma membrane. • This has oblique but parallel striations called Myonemes MYONEMES PELLICLE
- 12. • The pellicle is composed of fibrous elastic protein but not of cellulose • Pellicle maintains a definite shape of the body • It has an outer thin layer epiculticle and inner thick later cuticle Structure of Euglena viridis Cont’d
- 13. Cytostome & Cytopharynx: • At the anterior end is a funnel- shaped cytostome or cell mouth slightly to one side of the center • Cytostome leads into a short tubular cytopharynx or gullet • Both serve as a canal for escape of fluid from the reservoir
- 15. • It is a large osmoregulatory body • It lies near the reservoir on one side • The contractile vacuole discharges the excess of water and some waste products of metabolism into the reservoir Contractile Vacuole:
- 16. • long, whip-like flagellum emerges out of the cytostome through cytopharynx • Each root springs from a blepharoplast • There are two flagella, one long and the other short. Flagellum:
- 17. • Near the inner end of the cytopharynx close to the reservoir is a red eye spot or stigma • It function as a lens and is sensitive to light Stigma:
- 18. • Paraflagellar body lies either on one root or at the junction of two roots of the flagellum • The paraflagellar body is sensitive to light and it is regarded to be photoreceptor • Photoreceptor apparatus Paraflagellar Body:
- 19. • The cytoplasm of Euglena Viridis is differentiated into an outer layer of ectoplasm and inner layer of endoplasm Cytoplasm:
- 20. • Euglena has a single, large, round or oval and vesicular nucleus lying in a definite position • The nucleus contains a central body known as Endosome (which is also known as nucleolus or karyosome). Nucleus:
- 21. • Radiating from the center of the body of Euglena, there are several, slender, band like elongated chromatophores. • The chromatophores contain the green pigment, chlorophyll a and b and are also known as chloroplasts. • Euglena viridis derives its green colour from these chromatophores Chromatophores:
- 22. • Paramylum bodies of various shapes and sizes are found scattered throughout the endoplasm. • These are refractile bodies and contain stored food material in the form of paramylon Paramylon Bodies:
- 23. Movement In Euglena • There are two methods of locomotion in Euglena; 1. Flagellar movement 2. Euglenoid movement
- 24. Flagellar Movement: • Whip-like projection • Flagellum undergoes series of lateral movements where pressure is exerted on the water at right angles to its surface
- 25. Euglenoid Movement • Movement is called Metaboly • In this type , the organism shows a peculiar slow wriggling movement • Peristaltic wave of contraction and expansion trigger this movement
- 27. Mode of Nutrition • The mode of nutrition in Euglena is mixotrophic • Nutrition is accomplished either by holophytic or saprophytic or by both modes
- 28. Holophytic or Autotrophic Nutrition: • Food is manufactured photosynthetically, as in plants with the aid of carbon dioxide, light and chlorophyll in the chromatophores
- 29. Saprophytic / Saprozoic Nutrition: • In the absence of sunlight, Euglena derives its food by another mode of nutrition known as saprophytic, osmotrophic or saprozoic.
- 30. Respiration • Exchange of gases (intake of O2 and giving out of CO2) takes place by diffusion through the body surface.
- 31. • The elimination of carbon dioxide and nitrogenous waste product (ammonia) takes place through the general body surface by diffusion • At least some excretion, however, is carried out by the contractile vacuole. Excretion
- 32. • Water continuously enters a euglena body through osmosis due to its semi-permeable pellicle • Excess amount of water is remove from the body through osmoregulation • This is done by the contractile vacuole Osmoregulation:
- 33. Reproduction • Euglenoids do not reproduce sexually • Reproduction is by cell division • Longitudinal binary fission and multiple fission
- 34. Longitudinal Binary Fission: • In this type of fission, Euglena divides into two daughter euglenae, which are exactly identical to one another
- 36. Multiple Fission: • Euglena undergo repeated mitotic divisions giving rise to 16 – 32 small daughter individuals • This usually take place in encysted condition
- 37. • Euglena is a very important organism within the environment as it is able to photosynthesize, thus taking in carbon dioxide and releasing oxygen into the atmosphere so that other organisms can survive • Because they do this, they produce oxygen and so their economic value in the water is an intrinsic part of the ecosystem and, therefore is valuable Ecological & Economic Importance
- 38. Reference • Nabors, Murray W., Introduction To Botany. Copyright 2004 Pearson Education, Inc., publishing as Benjamin Cummings, 1301 Sansome St., San Francisco, CA 94111. www.aw-bc.com
- 39. → Les Brown “Accept responsibilities for your life. Know that it’s you who will get you where you want to go, no one else”
Editor's Notes
- Euglena gracilisis
- When something is spindle shaped, it is wide in the middle and tapers at both ends.
- periplast. : plasma membrane also : a proteinaceous subcellular layer below the plasma membrane especially of a euglena Pellicle a thin skin, cuticle, membrane, or film supporting the cell membrane in various protozoa FUNCTION: The pellicle is stiff to maintain the shape and provide stability it is also flexible to allow movement. It also acts as an attachment site for external organelles such as cilia.
- Elastic fibers are bundles of proteins (elastin) found in extracellular matrix of connective tissue Elastin is a highly elastic protein in connective tissue and allows many tissues in the body to resume their shape after stretching or contracting. Elastin helps skin to return to its original position when it is poked or pinched
- Cytostome - cell mouth Cytopharynx (gullet) : an invagination of the protoplasm in various protozoans (such as a paramecium) that sometimes functions in the intake of food Function as a throat or oesophagus for intake of food.
- OSMOREGULATION: the maintenance of constant osmotic pressure in the fluids of an organism by the control of water and salt concentrations. OSMOTIC PRESSURE: the pressure that would have to be applied to a pure solvent to prevent it from passing into a given solution by osmosis, often used to express the concentration of the solution. contractile vacuole. a membrane-enveloped cellular organelle, found in many microorganisms, that periodically expands, filling with water, and then contracts, expelling its contents to the cell exterior: FUNCTION: thought to be important in maintaining hydrostatic equilibrium (WATER BALANCE)
- long, whip-like flagellum emerges out of the cytostome through cytopharyn It arises by two roots from the base of the reservoir from the side opposite to the contractile vacuole. Each root springs from a Blepharoplast (basal body) Blepharopast is a protein structure found at the base of a eukaryotic orgnism
- Also called stigma A light-sensitive pigmented spot on the bodies of invertebrates such as flatworms, starfishes, and microscopic crustaceans, and also in some unicellular organism. functions in light reception They get their color from carotenoid pigments contained in bodies called pigment granules. The photoreceptors are found in the plasma membrane overlaying the pigmented bodies. The eyespot apparatus of Euglena comprises the paraflagellar body connecting the eyespot to the flagellum.
- Photoreceptor apparatus (Both Eyespot and Paraflagellar body)
- The endoplasm contains nucleus, chromatophores and paramylum bodies.
- Chromatophores are cells or plastids that contains pigment.
- The euglenoids have chlorophylls a and b and they store their photosynthate in an unusual form called paramylon starch, a B-1,3 polymer of glucose. The paramylon is stored in rod like bodies throughout the cytoplasm, called paramylon bodies, which are often visible as colorless or white particles in light microscopy. Their shape is often characteristic of the Euglenaspecies that produces them. Paramylon bodies (storage organs for paramylon starch)
- Euglenoid movement is the expansion and contraction of the cell body of various flagellates
- holophyte (plural holophytes) (biology) Any organism that produces its own food through photosynthesis When acting as a autotroph, the Euglena utilizes its chloroplasts (which gives it the green colour) to produce sugars by photosynthesis, when acting as a heterotroph, the Euglena surrounds the particle of food and consumes it by phagocytosis, or in other words, engulfing the food through its cell membrane.
- when acting as a heterotroph, the Euglena surrounds the particle of food and consumes it by phagocytosis, or in other words, engulfing the food through its cell membrane.
- Osmoregulation is the control of the levels of water and mineral salts in the body/blood The amounts of water and various mineral salts is also held constant; this is osmoregulation. Osmoregulation is very important: our tissues do not lose or gain water by osmosis because the concentrations of water and salts is the same inside and outside the cells. Osmoregulation is an important process in both plants and animals as it allows organisms to maintain a balance between water and minerals at the cellular level despite changes in the external environment.